1. Field of the Invention
The present invention relates to a suction cup (sucker).
2. Description of the Related Art
Suction cups for attaching goods to, for example, a wall in a room or to a dashboard in an automobile have been known.
Ordinarily, this kind of suction cup is formed in a circular disk-like shape from a rubber or the like, and its surface on one side in the thickness direction thereof is made to be a suction surface to be put into suction contact with a surface to be sucked, while its surface on the other side is made to be a back surface.
In use of the suction cup, the suction surface is made to front on the surface to be sucked, a central part of the suction surface is pressed against the surface to be sucked, whereby a substantially vacuum condition is generate between the suction surface of the suction cup and the surface to be sucked, and the vacuum condition is maintained by the elasticity of the suction cup, so as to leave the suction cup in suction contact with the surface to be sucked (refer to Japanese Patent Laid-open No. Hei 11-193811 as Patent Document 1).
On the other hand, in the cases where the surface to be sucked is formed as a grained surface or is formed as a minutely rugged surface, a rough surface or the like, it may be impossible to maintain the adhesion (close contact) between the suction surface and the surface to be sucked, and a gap may be formed between the suction surface and the surface to be sucked. Thus, it is difficult to maintain the suction contact performance of the suction cup.
In order to solve this problem, the present applicant has proposed a suction cup capable of adhesion to a surface to be sucked even in the cases where the surface to be sucked is formed as a grained surface or is formed as a minutely rugged surface, a rough surface or the like, wherein the suction surface of the suction cup includes a gel layer (Japanese Patent Application No. 2006-116359).